Ref HAL: hal-01909430_v1
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Some countries with rich textile industries are nowadays facing water quality issues as a consequence of impacting dye pollution. In addition to their inherent toxicity, dyes induce modification in water acidity or salinity which has harmful consequences on the photosynthesis of aquatic plants. As dye are hardly biodegradable, water treatment is necessary to get ride of them [1], and adsorption treatment appears as a good candidate with efficient low-cost adsorbents, such as clays [2]. As a matter of fact, lamellar materials are widely used for sorbtion of ions and molecules harmful for health and environment. In order to gain in efficiency in the use of such materials, it is essential to get a deeper understanding of the retention mechanisms at the interface solid/liquid. In this work, anionic clays, namely layered double hydroxides (LDH) have been chosen as model compounds in order to study sorption mechanism. The presence of charged layer induce strong anionic exchange capacity in these materials, moreover their composition and structual parameters are easily controled through mastered synthesis process [3]. This study work has been focused on the the mechanisms that can lead to the capture of polluting molecules. Several model dyes have been chosen (MethylOrange - MO, Carmen Indigo - CI et Orange G - OG) for their charge, symmetry and hydrophobicity. Parameters such as the solution concentration and the activity of the solvant, playing with the nature of ions, have also been explored.The work presented here rely on vibrational spectroscopies (Infrared and Raman spectroscopies) sensitive to the intermolecular interaction of the dye with its environment particularly at the interface solid/dye. In parallel, X-Ray Diffraction probes the structural modification in the clay during sorption.The experimental results interpreted though the help of simulations (Monte-Carlo, DFT), lead a fine description of ions sorption at the interfaces with these models lamellar materials.

Ref HAL: hal-01909394_v1
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Bridged silsesquioxane nanomaterials exhibit original mechanical properties thanks to the association of non-covalent and covalent interactions. Thanks to in situ high pressure spectroscopic studies, achieved in diamond anvil cells, the mechanical behavior of these materials was followed as a function of pressure. Figure 1: Schematic representation of bottom-up structuring in organic-inorganic hybrid silica through self-assembling process Vibrational studies on organic models coupled to ab-initio simulations show that H bond response to pressure is strengthening. In hybrid materials the H bond shows its ability to absorb the mechanical constrains by the modulation of H bond interactions. We thus show that the rigidity yielded by the inorganic polymerization is counterbalanced by the presence of the intermolecular H bond network. The hybrid materials have therefore a reversible behavior, thanks to h bonds behaving as molecular springs. For higher pressure ranges inorganic network start to be strongly impacted in a dominant way so that an irreversible loss of long range order within the organic network is observed.In a second time, the influence of the nature of the organic substructure (thiourea versus urea link, aryl versus aliphatic core) on this spring behavior is discussed.

Ref HAL: hal-01902659_v1
DOI: 10.1016/j.polymertesting.2018.07.007
WoS: 000445993600024
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3 Citations
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The degree of curing of epoxy composites and coatings is one key parameter to control the reliability of manufacturing processes, particularly in printed circuit board (PCB) manufacturing where epoxy buildup composites are partially cured before processing. We show that the reaction of curing of an industrially relevant buildup composite (epoxy-phenol reinforced with silica fillers) can be monitored by diffuse reflectance infrared Fourier transform (DRIFT) in the near-infrared range. The accuracy of DRIFT measurements is confirmed by comparison with measurements in transmission mode on reference composite samples. DRIFT is demonstrated to offer an easy and reliable measurement of the epoxy degree of curing on PCB coupons.

Ref HAL: hal-01884447_v1
DOI: 10.1021/acs.nanolett.8b02437
WoS: WOS:000441478300097
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16 Citations
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Mechanical resonators based on a singlecarbon nanotube are exceptional sensors of mass and force.The force sensitivity in these ultralight resonators is oftenlimited by the noise in the detection of the vibrations. Here,we report on an ultrasensitive scheme based on a RLCresonator and a low-temperature amplifier to detect nanotubevibrations. We also show a new fabrication process ofelectromechanical nanotube resonators to reduce the separation between the suspended nanotube and the gate electrodedown to ∼150 nm. These advances in detection and fabrication allow us to reach 0.5pm/ Hz displacement sensitivity.Thermal vibrations cooled cryogenically at 300 mK are detected with a signal-to-noise ratio as high as 17 dB. We demonstrate4.3zN/ Hz force sensitivity, which is the best force sensitivity achieved thus far with a mechanical resonator. Our work is animportant step toward imaging individual nuclear spins and studying the coupling between mechanical vibrations and electronsin different quantum electron transport regimes.

Ref HAL: hal-01881804_v1
DOI: 10.1016/j.tca.2018.07.019
WoS: 000444663600024
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9 Citations
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Despite an abundant literature on epoxy-amine systems, a complete description of the curing kinetics in epoxy-phenol composites was still lacking. In this study, the curing kinetics of an epoxy-phenol composite relevant to microelectronics industry is probed by isothermal and non-isothermal differential scanning calorimetry. An isoconversional analysis of the data reveals a significant contribution of the diffusion of molecular species to the activation energy, at low temperature and high degrees of curing. A model-fitting of the kinetics is performed in two successive steps: high-temperatures data are fitted with Arrhenius law and nth order autocatalytic model (where the diffusion contribution is neglected), whereas low-temperature data are fitted using Rabinowitch and modified-Williams-Landel-Ferry models (considering a diffusion contribution related to the glass transition). The chemical and diffusion contributions to the rate constants are calculated at various temperatures, clarifying the kinetics regimes with precision. Finally, the kinetics regimes are summarized in an improved time-temperature-transformation diagram.

Ref HAL: hal-01845473_v1
DOI: 10.23647/ca.md20180407
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Single-walled carbon nanotubes are functionalized with copper hexacyanoferrate nanoparticles for the liquid-solid extraction of cesium from liquid waste and contaminated water. The functionalization process is followed mainly by x-ray photoemission spectroscopy. Indeed, determining the chemical environment around carbon or nitrogen atoms allows to evidence the formation of covalent bounding. In addition, the signatures of iron and copper ions give information on the effective growth of hexacyanoferrate nanoparticles. Furthermore, the cesium sorption mechanism is investigated by comparing the peak intensities associated to the response of potassium and cesium ions. Finally, based on the liquid chromatography analyzes, the sorption of cesium with the functionalized carbon supports is studied. The main results of this work are the demonstration of both a good selectivity of cesium trapping and a high sorption capacity by hybrid single-walled carbon nanotubes.

Ref HAL: hal-01844602_v1
Ref Arxiv: 1712.01055
DOI: 10.1103/PhysRevE.98.012605
WoS: 000439065200005
Ref. & Cit.: NASA ADS
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6 Citations
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The number of precise conductance measurements in nanopores is quickly growing. To clarify the dominant mechanisms at play and facilitate the characterization of such systems for which there is still no clear consensus, we propose an analytical approach to the ionic conductance in nanopores that takes into account (i) electro-osmotic effects, (ii) flow slip at the pore surface for hydrophobic nanopores, (iii) a component of the surface charge density that is modulated by the reservoir pH and salt concentration cs using a simple charge regulation model, and (iv) a fixed surface charge density that is unaffected by pH and cs . Limiting cases are explored for various ranges of salt concentration and our formula is used to fit conductance experiments found in the literature for carbon nanotubes. This approach permits us to catalog the different possible transport regimes and propose an explanation for the wide variety of currently known experimental behavior for the conductance versus cs .